Correct valve positioning is crucial for treatment success and optimal outcomes after transcatheter valve implantation. For example, to maintain a stable and correct lengthwise position with respect to the aortic annulus, a stepwise deployment that allows the valve to be repositioned both circumferentially and in the axial direction (i.e., towards the left ventricle (LV) or the ascending aorta) is important.
However, most of the current technologies are limited by instant deployment, and once the valve is deployed, repositioning and/or percutaneous retrieval is not possible—or at least difficult or potentially problematic. Placement of a stented valve in a position that is too high (or proximal) can totally or partially obstruct the coronary ostia in a case of aortic implantation, which may result in myocardial infarction or ischemia. Additionally, if the valve is placed too high in the aorta, it may embolize into the aorta causing significant paravalvular regurgitation. On the other hand, implantation in a position that is too low (or distal) is accompanied by compression of the atrioventricular (AV) node in the membranous septum, which leads to conduction abnormalities.
Further technical developments with a focus on a positionable, repositionable, and/or percutaneously retrievable valve design would allow optimal placement and may thereby significantly reduce the risk of paravalvular aortic regurgitation, myocardial infarction, or ischemia related to improper positioning.